Rats chewing through cement tubs???

[sassy-pants]

But my question is, "Do rats normally chew through the cement tubs?" I have two tubs so far chewed through by the rats. Is this normal? Is there anything that can be done to deter them from chewing through?

No, they don't normally. It happens occasionally, but definitely shouldn't occur that often. Give them something else to chew on, like wood blocks, to help deter that behavior. Make sure they always have access to food and clean water, also. If they've got everything they need to be happy, they'll be less likely to try to escape.